Raised terminals on metallized ceramic packages are known. Such terminals have been made by, for example, braze build-up techniques, the application of refractory metal patterns by individual or multiple screenings to green (i.e., unfired) ceramic packages, or the lamination of a patterned refractory metal tape to unfired ceramic packages. While these techniques have met with some success, they have not been entirely satisfactory. For example, braze build-up techniques and multiple screening of refractory metal patterns often result in rounded terminals which are more difficult to probe during testing.
Additionally, these prior techniques do not provide selective or controlled solder wetting and flow when packages are attached by, for example, reflow soldering to electronic components. Consequently, excess solder is free to flow away from the terminal in any direction which may create electrical short circuits between the terminals.
With increasing miniaturization of electronic components and the resultant requirement that the terminals of the substrate be more closely spaced, the creation of electrical short circuits between terminals caused by the flow of excess solder is exacerbated. Consequently, it would be highly beneficial to provide terminals which are selectively wettable by solder so that the direction of the flow of excess solder can be controlled. Moreover, controlled flow of the solder is highly desirable as it can provide the fill-in necessary to correct for camber present in the package.
Ceramic packages which utilize selectively metallized terminals have been disclosed in U.S. Pat. Nos. 3,271,507 and 3,404,214. These patents disclose packaging devices in which grooves and selected unmetallized sections define conductive areas. Semiconductive devices are bonded to a surface of a channel in such a package. Ohmic contact is then made between the semiconductive device and a conductive area. Conductive areas are metallized by conventional techniques such as spraying, rolling, etc.
Copending application Ser. No. 191,329 filed Sept. 26, 1980, discloses ceramic articles having raised bas-relief or embossed coated configurations which are inconnective configurations. These articles are prepared by pressing the article into the desired shape from a suitable ceramic followed by transfer of a suitable conductive material to the desired surfaces of the molded article. The conductive material may be transferred from a tape to the ceramic, inking, etc.